百慕大西南二级飓风“伊梅尔达”(09L.Imelda) - 与Humberto共舞，影响巴哈马群岛 - NHC:85KT

pocketbox

WTNT44 KNHC 281451
TCDAT4

Tropical Depression Nine Discussion Number   8
NWS National Hurricane Center Miami FL       AL092025
1100 AM EDT Sun Sep 28 2025

Structurally, the depression continues to gradually become better
organized, with an attempt at more bursting convection closer to the
estimated center. However, recent observations from the ongoing Air
Force Reserve Reconnaissance aircraft mission have been rather
underwhelming, which still shows a broad wind field and a peak
850-mb wind of only 37 kt. Based on this information, the system
will remain a depression for this advisory with maximum sustained
wind of 30 kt, which is a little under the satellite-based
intensity estimates.

The depression has not really accelerated much yet this morning, and
it appears to be moving slowly northward at 350/6 kt. A general
north-northwest to northward motion is expected to continue for the
next 24-36 hours as southerly steering persists from both an upper
trough over the southeastern United States and the subtropical ridge
centered just east of Bermuda. After that period of time, the
subtropical ridge's steering influence decreases as Hurricane
Humberto's larger outer circulation creates a large weakness. Given
the slow motion of the depression so far, it has also remained
south of a track bifurcation point that was seen yesterday in the
ensemble guidance. The tropical cyclone now appears more likely to
turn sharply east-northeastward starting on Tuesday and continuing
through the remainder of the forecast. The track guidance this cycle
has made another south and eastward shift, and the NHC track
forecast has been moved in that direction. In particular, the
track guidance continues to show much more east-northeastward
acceleration at the end of the forecast, requiring large speed
changes in days 4 and 5, and this still might not be fast enough.
The latest track forecast is very close to the HCCA consensus aid,
but blends it with a little more of the Google DeepMind ensemble
mean (GDMI) by the day 5 forecast.

While the depression has not yet developed an inner core, one is
expected to form in the next 12-24 hours. Some southerly vertical
wind shear is expected to persist, though it never gets
prohibitively strong, remaining under 20 kt for the next 48-72 h in
the GFS-based SHIPS. Therefore, intensification is expected and the
latest NHC intensity forecast is roughly in line with the intensity
guidance consensus aids. In 3-4 days, the cyclone is expected to
find itself in the right entrance region of an intensifying
upper-level jet, and the enhanced upper-level divergence in that
time may help support additional intensification even as the shear
begins to increase towards the end of the forecast. After the system
passes Bermuda, a strong baroclinic zone is expected to interact
with the system, resulting in extratropical transition by day 5 as
it gets tangled up with a frontal boundary. However, as stressed
previously, this is a low confidence forecast at long range given
the recent large track changes, especially since the southward shift
in track keeps the cyclone over warmer sea-surface temperatures.

KEY MESSAGES:

1. The depression is expected to strengthen and bring tropical storm
conditions to portions of the central and northwestern Bahamas
through Monday. Tropical storm conditions are also possible
along portions of the east coast of central Florida beginning
Monday.

2. Rainfall associated with the system will continue to impact
eastern Cuba and the Bahamas through Tuesday, which will likely
produce flash and urban flooding.  Mudslides are possible in the
higher terrain.  Heavy rainfall across the coastal Carolinas could
cause flash, urban, and river flooding into Wednesday morning.

3. The risk of significant wind impacts along the southeastern
United States coast is decreasing, but interests in that area should
continue to monitor the latest forecast updates.

4. Swells and high surf from both Humberto and Tropical Depression
Nine are expected to produce dangerous marine conditions and rip
currents along the east coast of Florida and the Georgia coast
through Monday.  These conditions are expected to spread northward
along much of the east coast of the United States early this week.


FORECAST POSITIONS AND MAX WINDS

INIT  28/1500Z 23.5N  77.3W   30 KT  35 MPH
12H  29/0000Z 24.5N  77.4W   40 KT  45 MPH
24H  29/1200Z 26.2N  77.6W   50 KT  60 MPH
36H  30/0000Z 27.7N  77.6W   60 KT  70 MPH
48H  30/1200Z 28.8N  77.1W   65 KT  75 MPH
60H  01/0000Z 29.3N  75.7W   70 KT  80 MPH
72H  01/1200Z 29.9N  73.5W   75 KT  85 MPH
96H  02/1200Z 31.0N  68.0W   80 KT  90 MPH
120H  03/1200Z 32.5N  61.5W   70 KT  80 MPH...POST-TROP/EXTRATROP

$$
Forecaster Papin

ygsj24

000
WTNT34 KNHC 281749
TCPAT4

BULLETIN
Tropical Storm Imelda Intermediate Advisory Number 8A
NWS National Hurricane Center Miami FL       AL092025
200 PM EDT Sun Sep 28 2025

...DEPRESSION BECOMES TROPICAL STORM IMELDA...
...TROPICAL STORM CONDITIONS EXPECTED OVER THE CENTRAL AND
NORTHWESTERN BAHAMAS THIS AFTERNOON AND EVENING...

SUMMARY OF 200 PM EDT...1800 UTC...INFORMATION
----------------------------------------------
LOCATION...23.9N 77.3W
ABOUT 95 MI...155 KM WNW OF THE CENTRAL BAHAMAS
ABOUT 370 MI...600 KM SE OF CAPE CANAVERAL FLORIDA
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...N OR 355 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...998 MB...29.47 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...
* Central Bahamas, including Cat Island, the Exumas, Long Island,
Rum Cay, and San Salvador
* Portions of the northwestern Bahamas, including Eleuthera, New
Providence, the Abacos, Berry Islands, Andros island, and Grand
Bahama Island

A Tropical Storm Watch is in effect for...
* East coast of Florida from the Palm Beach/Martin County Line to
the Flagler/Volusia County Line

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area, within 36 hours.

A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.

Interests elsewhere in the Bahamas and along the southeast coast of
the United States should monitor the progress of this system.

For storm information specific to your area in the United
States, including possible inland watches and warnings, please
monitor products issued by your local National Weather Service
forecast office. For storm information specific to your area
outside of the United States, please monitor products issued by
your national meteorological service.


DISCUSSION AND OUTLOOK
----------------------
At 200 PM EDT (1800 UTC), the center of Tropical Storm Imelda was
located by Air Force reconnaissance data near latitude 23.9 North,
longitude 77.3 West. Imelda is moving toward the north near 7 mph
(11 km/h). A faster motion to the north is expected later today and
continuing through Monday. On the forecast track, the center of the
system is expected to move across the central and northwestern
Bahamas this afternoon and tonight and then turn east-northeastward,
moving away from the southeastern U.S. by the middle part of this
week.

Maximum sustained winds have increased to near 40 mph (65 km/h) with
higher gusts. Strengthening is expected during the next few days,
and Imelda is forecast to become a hurricane by late Monday or
Tuesday.

Tropical-storm-force winds extend outward up to 30 miles (50 km)
from the center.

The minimum central pressure estimated by aircraft dropsonde data is
998 mb (29.47 inches).


HAZARDS AFFECTING LAND
----------------------
Key messages for Tropical Storm Imelda can be found in the
Tropical Cyclone Discussion under AWIPS header MIATCDAT4 and WMO
header WTNT44 KNHC.

WIND: Tropical storm conditions are occuring in the central Bahamas
and are expected in the northwestern Bahamas later this afternoon.
Tropical storm conditions are possible in the watch area along the
east coast of Florida on Monday.

RAINFALL: Tropical Storm Imelda is expected to produce additional
rainfall of 2 to 6 inches across eastern Cuba and 6 to 12 inches
across the northwest Bahamas through Tuesday. This rainfall will
likely produce flash and urban flooding. Mudslides are also possible
in areas of higher terrain across eastern Cuba.

Storm total rainfall amounts of 2 to 4 inches with local maxima of
7 inches are expected into Wednesday morning across portions of the
coastal Carolinas. This rainfall could result in flash, urban, and
isolated, minor river flooding. Changes in the forecast track could
result in further adjustments to these rainfall totals.

For a complete depiction of forecast rainfall and flash flooding
associated with this system, please see the National Weather
Service Storm Total Rainfall Graphic, available at
hurricanes.gov/graphics_at4.shtml?rainqpf and the Flash Flood Risk
graphic at hurricanes.gov/graphics_at4.shtml?ero

STORM SURGE: A storm surge will raise water levels by as much as 1
to 3 feet above ground level along the immediate coast in areas of
onshore winds in the northwestern Bahamas. Near the coast, the
surge will be accompanied by large waves.

Minor coastal flooding is possible in areas of onshore winds over
the Southeastern U.S. coastline. The water could reach the
following heights above ground somewhere in the indicated areas if
the surge occurs over the next several high tide cycles...

Volusia/Brevard County Line, Florida to the South Santee River,
South Carolina...1 to 2 ft

SURF: Swells generated by Tropical Storm Imelda and Hurricane
Humberto will affect portions of the Bahamas this weekend, and
spread to much of the east coast of the U.S. early this week. These
swells are likely to cause life-threatening surf and rip current
conditions. Please consult products from your local weather office.

A depiction of rip current risk for the United States can be found
at: hurricanes.gov/graphics_at4.shtml?ripCurrents


NEXT ADVISORY
-------------
Next complete advisory at 500 PM EDT.

$$
Forecaster Papin

ygsj24

000
WTNT44 KNHC 282053
TCDAT4

Tropical Storm Imelda Discussion Number   9
NWS National Hurricane Center Miami FL       AL092025
500 PM EDT Sun Sep 28 2025

In the last outbound northeast leg, the Air Force reconnaissance
flying through the system found 850 mb flight level winds of 43 kt,
high enough to support upgrading Tropical Depression 9 to Tropical
Storm Imelda at the 18 UTC intermediate advisory. On that last fix,
a dropsonde launched in the center had a 1000 mb pressure, but with
a 34 kt surface wind gust that could be related to a nearby
convective feature, and a 998 mb pressure is used as the minimum
pressure. The initial intensity remains at 35 kt this advisory,
which is on the low side of the mean of the satellite estimates,
which range from 35-45 kt.

A more established motion with Imelda appears to finally be occuring
this afternoon, due northward at 360/8 kt. A general northward
motion is expected to continue over the next day or so as southerly
steering persists from both an upper trough over the southeastern
United States and the subtropical ridge centered just east of
Bermuda. After that period of time, the subtropical ridge's steering
influence decreases as Hurricane Humberto's larger outer circulation
creates a large weakness. The end result of this pattern change is
that Imelda is now forecast to turn sharply east-northeastward into
this weakness, starting on Tuesday and continuing through the
remainder of the forecast period, following behind Humberto. The
track guidance this cycle has finally started to stabilize near the
previous forecast track, though is still a tick faster than the
previous forecast cycle, and quite a bit of along-track spread
remains in the 4-5 day time frame. The NHC track forecast lies in
between the GFS and ECMWF track solutions, closest to but not quite
as fast as the Google DeepMind ensemble mean (GDMI).

Imelda's structure is gradually becoming better organized, with more
curvature in the convective bands on its eastern side, though the
earlier burst closer to the center has waned. Assuming a better
developed core forms soon, low to moderate vertical wind shear
between 15-20 kt, warm 28-30 C sea-surface temperatures, and
sufficient mid-level moisture should promote steady intensification
over the next 2-3 days. In 3-4 days, the cyclone is expected to find
itself in the right entrance region of an intensifying upper-level
jet, and the enhanced upper-level divergence in that time may help
support additional intensification even as the shear begins to
increase at this period. After the system passes Bermuda, a strong
baroclinic zone is expected to interact with the system, resulting
in extratropical transition by day 5 as it gets tangled up with a
frontal boundary. However, as stressed previously, this is a low
confidence forecast at long range given the recent large track
changes. In fact, simulated satellite imagery from the 12 UTC ECMWF
still suggests Imelda may produce significant convective bursts
while still over warm ocean waters in the day 4-5 forecast period.


KEY MESSAGES:

1. Imelda is expected to strengthen and bring tropical storm
conditions to portions of the central and northwestern Bahamas
through Monday.

2. Rainfall associated with Tropical Storm Imelda will continue to
impact eastern Cuba and the Bahamas through Tuesday, which will
likely produce flash and urban flooding.  Mudslides are possible in
the higher terrain.  Heavy rainfall across the coastal Carolinas
could cause isolated flash, urban, and river flooding through
Tuesday.

3. The risk of significant wind impacts along the southeastern
United States coast is decreasing, but interests in that area should
continue to monitor the latest forecast updates.

4. Swells and high surf from both Humberto and Imelda are expected
to produce dangerous marine conditions and rip currents along the
east coast of Florida and the Georgia coast through Monday.  These
conditions are expected to spread northward along much of the east
coast of the United States early this week.


FORECAST POSITIONS AND MAX WINDS

INIT  28/2100Z 24.2N  77.3W   35 KT  40 MPH
12H  29/0600Z 25.5N  77.4W   45 KT  50 MPH
24H  29/1800Z 27.2N  77.4W   55 KT  65 MPH
36H  30/0600Z 28.4N  77.2W   60 KT  70 MPH
48H  30/1800Z 29.2N  75.8W   65 KT  75 MPH
60H  01/0600Z 29.8N  73.9W   70 KT  80 MPH
72H  01/1800Z 30.7N  70.7W   80 KT  90 MPH
96H  02/1800Z 31.8N  63.2W   80 KT  90 MPH
120H  03/1800Z 33.5N  58.5W   65 KT  75 MPH...POST-TROP/EXTRATROP

$$
Forecaster Papin

ygsj24

078
WTNT44 KNHC 290237
TCDAT4

Tropical Storm Imelda Discussion Number  10
NWS National Hurricane Center Miami FL       AL092025
1100 PM EDT Sun Sep 28 2025

Imelda's cloud pattern has shown little change since earlier today.
There is a prominent band of deep convection over the eastern
portion of the circulation.  Some deep convection is developing
near/over the estimated center position.  Flight-level
winds observations from Air Force and NOAA Hurricane Hunter
aircraft investigating the storm indicate that the maximum winds
remain near 35 kt, although the recent increase of central
convection suggests some strengthening may soon occur.   

Center fixes from the Hurricane Hunters show that the motion has
been mainly northward with the initial motion estimate remaining
about 360/8 kt.  Imelda should continue this generally northward
track through tomorrow while moving on the western side of a
mid-level ridge.  Then, a trough over the southeastern U.S. is
expected to cause the cyclone to turn sharply east-northeastward.  
This track should keep the center of Imelda offshore of the
southeastern U.S. coast.  Later in the forecast period, the system
should move mainly east-northeastward over the subtropical
Atlantic, and pass near Bermuda in several days.  The official
track forecast is similar to the one from the previous
advisory, and close to the model consensus.

Imelda is expected to remain in an environment of moderate
south-southwesterly vertical wind shear for the next few days.  The
system will be moving over warm ocean waters of around 29 deg C and
within a fairly moist mid-level air mass.  Given the mainly
conducive environmental conditions, the cyclone is likely to
strengthen into a hurricane within the next 1-2 days, with
additional intensification likely thereafter.  The official
intensity forecast is at the higher end of the model guidance.  By
the end of the forecast period, simulated satellite imagery from
the global models suggest the cloud pattern of an extratropical
cyclone, and the official forecast shows extratropical transition
around that time.

KEY MESSAGES:

1. Imelda is expected to continue to bring tropical storm
conditions to portions of the central and northwestern Bahamas
through Monday.

2. Rainfall associated with Imelda will continue to impact eastern
Cuba and the Bahamas through Tuesday, which will likely produce
flash and urban flooding.  Mudslides are possible in the higher
terrain.  Heavy rainfall across the coastal Carolinas could cause
isolated flash and urban flooding through Tuesday.

3. The risk of significant wind impacts along the southeastern
United States coast is decreasing, but interests in that area should
continue to monitor the latest forecast updates.

4. Swells and high surf from both Humberto and Imelda are expected
to produce dangerous marine conditions and rip currents along the
east coast of Florida and the Georgia coast through Monday.  These
conditions are expected to spread northward along much of the east
coast of the United States early this week.


FORECAST POSITIONS AND MAX WINDS

INIT  29/0300Z 25.0N  77.1W   35 KT  40 MPH
12H  29/1200Z 26.3N  77.2W   45 KT  50 MPH
24H  30/0000Z 27.9N  77.3W   55 KT  65 MPH
36H  30/1200Z 28.8N  76.5W   65 KT  75 MPH
48H  01/0000Z 29.4N  74.8W   70 KT  80 MPH
60H  01/1200Z 30.2N  72.0W   75 KT  85 MPH
72H  02/0000Z 31.2N  68.3W   80 KT  90 MPH
96H  03/0000Z 33.4N  61.0W   80 KT  90 MPH
120H  04/0000Z 36.5N  56.7W   65 KT  75 MPH...POST-TROP/EXTRATROP

$$
Forecaster Pasch

pocketbox

全球热带气旋监测公报
预报：徐立、张增海  签发：柳龙生  2025 年 09 月 29 日 10 时
“伊梅尔达”生成

时        间:   29日08时

海        域:    北大西洋

命        名:    “伊梅尔达”，IMELDA

中心位置:    西经77.1度，北纬24.6度

强度等级:    热带风暴

最大风力:    8级，18米/秒，相当于我国的热带风暴级

中心气压:    998百帕

参考位置:    距离北大西洋美国佛罗里达州迈阿密东南方向约365公里

预报结论:   “伊梅尔达”将以每小时15公里左右的速度向偏北方向移动，强度逐渐加强。



图2 卫星红外监测图像（北京时间2025年9月29日08时00分）

pocketbox

全球热带气旋监测公报
预报：徐立、张增海  签发：柳龙生  2025 年 09 月 29 日 18 时
“伊梅尔达”向偏北方向移动

时        间:   29日14时

海        域:    北大西洋

命        名:    “伊梅尔达”，IMELDA

中心位置:    西经77.1度，北纬25.1度

强度等级:    热带风暴

最大风力:    8级，20米/秒，相当于我国的热带风暴级

中心气压:    998百帕

参考位置:    距离北大西洋美国佛罗里达州西棕榈滩东南方向约340公里

预报结论:   “伊梅尔达”将以每小时15公里左右的速度向偏北方向移动，强度逐渐加强。



图2 卫星红外监测图像（北京时间2025年9月29日14时00分）

pocketbox

WTNT44 KNHC 290856
TCDAT4

Tropical Storm Imelda Discussion Number  11
NWS National Hurricane Center Miami FL       AL092025
500 AM EDT Mon Sep 29 2025

Imelda continues to slowly become better organized.  Earlier
aircraft data indicated that the pressure has fallen to 996 mb, and
satellite imagery shows persistent convection near and north of the
center.  The initial intensity is set to 40 kt with numerous 35 kt
wind vectors on the evening scatterometer pass and higher Dvorak
estimates.  

The storm is progressing northward at about 7 kt.  This motion is
forecast to continue today due to steering along the western side
of the subtropical ridge.  Humberto is forecast to erode the ridge
by Tuesday, causing an abrupt turn of Imelda to the east-northeast
with some acceleration as the cyclone encounters faster mid-
latitude flow.  There is increasing confidence in the storm staying
well offshore of the southeastern United States coast.  The
latest track guidance is similar to the previous cycle, although
faster at the end, and remains close to Bermuda.  The medium range
forecast beyond Bermuda is quite uncertain with a complicated flow
pattern due to a digging north Atlantic trough and
then-extratropical Humberto interactions.

Imelda is forecast to gradually strengthen within an environment of
moderate south-southwesterly vertical wind shear, warm ocean waters
and within a fairly moist mid-level air mass for the next couple of
days.  Thereafter, an upper-level trough will help to initiate
extratropical transition, and some of the models are showing this
as a favorable trough interaction, causing a larger and stronger
cyclone.  The GFS and ECMWF models are also showing a sting jet
developing as well about the time that Imelda is near Bermuda, so
that situation will have to be watched closely.  The official
forecast remains at the higher end of the model guidance.  Most of
the global models are showing a faster extratropical transition
after Imelda moves past Bermuda, and that is indicated in the new
NHC forecast.


KEY MESSAGES:

1. Imelda is expected to continue to bring tropical storm conditions
to portions of the northwestern Bahamas today.

2. Rainfall associated with Imelda will continue to impact eastern
Cuba and the Bahamas through Tuesday, which will likely produce
flash and urban flooding.  Mudslides are possible in the higher
terrain.  Heavy rainfall across the coastal Carolinas could cause
isolated flash and urban flooding through Tuesday.

3. Interests in Bermuda should monitor the progress of Imelda as a
Hurricane Watch could be required late today.

4. Swells and high surf from both Humberto and Imelda are expected
to produce dangerous marine conditions and rip currents along the
east coast of Florida and the Georgia coast today.  These conditions
are expected to spread northward along much of the east coast of the
United States early this week.


FORECAST POSITIONS AND MAX WINDS

INIT  29/0900Z 25.5N  77.1W   40 KT  45 MPH
12H  29/1800Z 26.7N  77.1W   50 KT  60 MPH
24H  30/0600Z 28.1N  76.8W   60 KT  70 MPH
36H  30/1800Z 28.9N  75.1W   65 KT  75 MPH
48H  01/0600Z 29.9N  72.3W   70 KT  80 MPH
60H  01/1800Z 31.1N  68.8W   75 KT  85 MPH
72H  02/0600Z 32.4N  63.8W   80 KT  90 MPH
96H  03/0600Z 35.0N  56.0W   70 KT  80 MPH...POST-TROP/EXTRATROP
120H  04/0600Z 39.5N  52.5W   60 KT  70 MPH...POST-TROP/EXTRATROP

$$
Forecaster Blake

pocketbox

WTNT44 KNHC 291459
TCDAT4

Tropical Storm Imelda Discussion Number  12
NWS National Hurricane Center Miami FL       AL092025
1100 AM EDT Mon Sep 29 2025

Imelda is strengthening this morning. We have had plenty of data
from both the NOAA and Air Force Reserve Hurricane Hunters, and both
of their observations show that the tropical storm is becoming
better organized. This matches the improving structure on satellite
which shows a bursting central dense overcast. However, Tail Doppler
Radar (TDR) analysis still shows some modest tilt north with height
between the 1 km and 5 km centers. The peak 750 mb flight level
winds from the NOAA-P3 was up to 59 kt to the northeast of the
center, and the most recent dropsonde from the C-130 center fix was
990 mb with 20 kt of wind. Thus, the initial intensity for Imelda
has been raised to 50 kt this advisory, with a minimum pressure of
988 mb. The northwest Bahamas continue to get tropical storm
conditions, and there was a recent wind gust to 72 kt at Treasure
Cay.

The tropical storm continues to move northward at about 7 kt.  This
motion is forecast to continue today due to steering along the
western side of the subtropical ridge and eastern side of a mid to
upper-level trough located over the southeastern U.S. The steering
from the subtropical ridge is about to become interrupted by
Hurricane Humberto's large circulation as the upstream trough starts
to dig in behind Imelda. The combination of these changes will cause
the tropical cyclone's track to shift abruptly east-northeastward as
it accelerates. The latest track guidance is fairly similar to the
previous cycle, though there remains a substantial amount of
along-track spread over the 36-60 h period, where the ECMWF is on
the slow end of the guidance envelope, and the GFS and Google
DeepMind ensemble mean (GDMI) are on the faster end. The latest NHC
track forecast is along the prior forecast track, but a little
faster after 36 h, blending the HCCA and GDMI track guidance. On the
current forecast track, the center of Imelda is forecast to pass
near Bermuda in about 60-h, though the exact timing of this remains
low confidence.

Evidence from both the aircraft and satellite observations show that
Imelda is beginning to develop an inner core, and further
intensification is expected in a low to moderate vertical wind shear
environment along with sufficient mid-level moisture and plenty warm
sea-surface temperatures. In 48-60 h, the shear begins to increase
dramatically and the storm could pass near the cold wake of
Humberto. However, Imelda is also likely to get a intensity boost
from a favorable trough interaction, which could enhance the winds
along the cyclone's northwestern flank, and a higher 85 kt peak is
now shown during this time. This enhancement could evolve into a
"sting jet" like feature as the system becomes extratropical. The
timing of this transition remains difficult to determine, since the
ECMWF forecast is much slower and further south, keeping the cyclone
over warmer SSTs. My best guess is that this process will be
complete between the 72 to 96 h forecast points. The official
forecast remains at the higher end of the model guidance, but is
pretty close to the HCCA consensus aid.


KEY MESSAGES:

1. Imelda is expected to continue to bring tropical storm conditions
to portions of the northwestern Bahamas today.

2. Rainfall associated with Tropical Storm Imelda will continue to
impact the Bahamas through Tuesday, which will likely produce flash
and urban flooding.  Heavy rainfall across the coastal Carolinas
could cause isolated flash and urban flooding through Tuesday.

3. Interests in Bermuda should monitor the progress of Imelda as a
Hurricane Watch could be required this afternoon.

4. Swells and high surf from both Humberto and Imelda are expected
to produce dangerous marine conditions and rip currents along much
of the East Coast of the United States during the next several days.


FORECAST POSITIONS AND MAX WINDS

INIT  29/1500Z 26.9N  77.1W   50 KT  60 MPH
12H  30/0000Z 28.0N  77.0W   60 KT  70 MPH
24H  30/1200Z 29.0N  75.9W   70 KT  80 MPH
36H  01/0000Z 29.7N  73.6W   75 KT  85 MPH
48H  01/1200Z 30.8N  70.2W   80 KT  90 MPH
60H  02/0000Z 32.3N  65.4W   85 KT 100 MPH
72H  02/1200Z 33.7N  60.0W   80 KT  90 MPH
96H  03/1200Z 38.0N  53.0W   60 KT  70 MPH...POST-TROP/EXTRATROP
120H  04/1200Z 43.0N  49.0W   55 KT  65 MPH...POST-TROP/EXTRATROP

$$
Forecaster Papin

ygsj24

031
WTNT34 KNHC 291742
TCPAT4

BULLETIN
Tropical Storm Imelda Intermediate Advisory Number 12A
NWS National Hurricane Center Miami FL       AL092025
200 PM EDT Mon Sep 29 2025

...IMELDA STARTING TO MOVE NORTH OF THE BAHAMAS...
...TROPICAL STORM CONDITIONS TO CONTINUE OVER THE NORTHWEST BAHAMAS
FOR A FEW MORE HOURS...


SUMMARY OF 200 PM EDT...1800 UTC...INFORMATION
----------------------------------------------
LOCATION...27.2N 77.3W
ABOUT 55 MI...90 KM N OF GREAT ABACO ISLAND
ABOUT 220 MI...355 KM ESE OF CAPE CANAVERAL FLORIDA
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...N OR 355 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...988 MB...29.18 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...
* Portions of the Northwestern Bahamas, including Eleuthera, the
Abacos, Grand Bahama Island and the surrounding keys.

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area in this case within 12
hours.

Interests in Bermuda should monitor the progress of Imelda.
Hurricane watches could be required for the island as soon as this
afternoon.

For storm information specific to your area, please monitor
products issued by your national meteorological service.


DISCUSSION AND OUTLOOK
----------------------
At 200 PM EDT (1800 UTC), the center of Tropical Storm Imelda was
located by Air Force Reserve reconnaissance aircraft near latitude
27.2 North, longitude 77.3 West. Imelda is moving toward the north
near 9 mph (15 km/h), and a general northward motion is expected to
continue today. On Tuesday, Imelda is expected to turn sharply to
the east-northeast. On the forecast track, the center of the system
is expected to start moving away from the northwestern Bahamas this
afternoon and then turn east-northeastward, moving away from the
southeastern U.S. but approach the island of Bermuda by the middle
part of this week.

Maximum sustained winds are near 60 mph (95 km/h) with higher gusts.
Additional strengthening is forecasted over the next several days,
and Imelda is forecast to become a hurricane on Tuesday.

Tropical-storm-force winds extend outward up to 175 miles (280 km)
from the center.

The minimum central pressure estimated by Air Force Reconnaissance
dropsonde data is is 988 mb (29.18 inches).


HAZARDS AFFECTING LAND
----------------------
Key messages for Tropical Storm Imelda can be found in the
Tropical Cyclone Discussion under AWIPS header MIATCDAT4 and WMO
header WTNT44 KNHC.

WIND: Tropical storm conditions are occuring in portions of
the northwestern Bahamas and should continue through the afternoon.

RAINFALL:  Tropical Storm Imelda is expected to produce total
rainfall of 4 to 8 inches across the northwest Bahamas through
Tuesday. This rainfall will likely produce flash and urban
flooding.

Storm total rainfall amounts of 1 to 2 inches with local maxima of 4
inches are expected through Tuesday across northeast Florida,
coastal South Carolina, and coastal sections of southeast North
Carolina. This rainfall could result in isolated flash and urban
flooding.

As Imelda passes near Bermuda, 2 to 4 inches – 50 to 100 mm – of
rainfall is expected from Wednesday into Thursday.

For a complete depiction of forecast rainfall and flash flooding
associated with Tropical Storm Imelda, please see the National
Weather Service Storm Total Rainfall Graphic, available at
hurricanes.gov/graphics_at4.shtml?rainqpf and the Flash Flood Risk
graphic at hurricanes.gov/graphics_at4.shtml?ero

STORM SURGE: A storm surge will raise water levels by as much as 1
to 3 feet above ground level along the immediate coast in areas of
onshore winds in the northwestern Bahamas.  Near the coast, the
surge will be accompanied by large waves.

Minor coastal flooding is possible in areas of onshore winds over
the Southeastern U.S. coastline. The water could reach the
following heights above ground somewhere in the indicated areas if
the surge occurs over the next several high tide cycles...

Volusia/Brevard County Line, Florida to the South Santee River,
South Carolina...1 to 2 ft

SURF: Swells generated by Tropical Storm Imelda and Hurricane
Humberto are affecting the Bahamas and will spread to much of the
east coast of the U.S. early this week. These swells are likely to
cause life-threatening surf and rip current conditions. Please
consult products from your local weather office.

A depiction of rip current risk for the United States can be found
at: hurricanes.gov/graphics_at4.shtml?ripCurrents


NEXT ADVISORY
-------------
Next complete advisory at 500 PM EDT.

$$
Forecaster Papin

ygsj24

000
WTNT44 KNHC 292053
TCDAT4

Tropical Storm Imelda Discussion Number  13
NWS National Hurricane Center Miami FL       AL092025
500 PM EDT Mon Sep 29 2025

Since the prior advisory, Imelda's structure on satellite imagery
continues to improve. Curved bands are now wrapping around the
western side of the tropical storm's circulation, and the last few
fixes from the NOAA and Air Force Reserve Hurricane Hunters did show
enhanced winds wrapping around the western side, becoming more
symmetric, though some northward tilt with height was still
persisting on the last Tail Doppler Radar (TDR) swath from the
NOAA-P3 aircraft. Satellite intensity estimates have continued to
gradually rise since that time, so the initial intensity is being
raised to 55 kt this advisory, in best agreement with the SAB
subjective Dvorak fix of T3.5/55-kt and the latest SATCON intensity
estimate of 54 kt.

Imelda continues to move northward, estimated at 360/8 kt. This
motion should continue through tonight, but as Humberto erodes the
steering influence of a subtropical ridge east of Bermuda, the
cyclone is expected to make a sharp turn to the east-northeast as
the storm steering becomes dominated by the deep-layer trough that
is digging southward upstream of Imelda. The latest track guidance
trajectory is quite similar to the prior cycle, though it has once
again shifted a bit faster beyond 36 h. There also remains a
substantial amount of along-track spread in both the deterministic
and ensemble guidance this afternoon. The NHC track forecast is a
little faster than the prior cycle, once again attempting to blend
the HCCA and Google DeepMind ensemble mean (GDMI). Based on the
forecast track, tropical storm conditions are expected to begin on
the Island of Bermuda in about 48 h, and in response, the Bermuda
Weather Service has issued a Hurricane Watch for the island this
advisory.

Further intensification is expected over the next several days as
Imelda remains in a low to moderate vertical wind shear environment
along with sufficient mid-level moisture and warm sea-surface
temperatures above 28 C. In 48-60 h, the shear starts quickly
increasing, but a favorable trough interaction may temper this
negative factor initially. This interaction may enhance the winds
along the cyclone's western flank, as seen in the most recent set of
hurricane-regional model runs. These enhanced winds may then evolve
into a "sting jet" like feature as the system becomes extratropical
in the 60-72 h time frame. The exact timing of this transition
remains difficult to forecast, since the cyclone will still be under
fairly warm SSTs at 60-72 h. The official intensity forecast is on
the high side of the guidance envelope, but near the HCCA consensus
aid.


KEY MESSAGES:

1. Imelda is expected to intensify into a hurricane on Tuesday with
the cyclone approaching Bermuda during the day Wednesday as a
hurricane. A Hurricane Watch is now in effect for the island of
Bermuda due to the expected onset of tropical storm conditions
beginning Wednesday afternoon.

2. Tropical storm conditions are expected to continue for another
few hours on Great Abaco and Grand Bahama island in the northwestern
Bahamas.

2. Rainfall associated with Tropical Storm Imelda will continue to
impact the Bahamas through tonight, which may produce flash and
urban flooding.  Locally heavy rainfall across the coastal Carolinas
could cause isolated flash and urban flooding through tonight.

3. Swells and high surf from both Humberto and Imelda are expected
to produce dangerous marine conditions and rip currents along much
of the East Coast of the United States during the next several days.


FORECAST POSITIONS AND MAX WINDS

INIT  29/2100Z 27.7N  77.3W   55 KT  65 MPH
12H  30/0600Z 28.4N  76.8W   65 KT  75 MPH
24H  30/1800Z 29.3N  75.0W   70 KT  80 MPH
36H  01/0600Z 30.4N  72.2W   75 KT  85 MPH
48H  01/1800Z 31.7N  67.8W   80 KT  90 MPH
60H  02/0600Z 33.3N  62.3W   85 KT 100 MPH
72H  02/1800Z 35.0N  56.8W   75 KT  85 MPH...POST-TROP/EXTRATROP
96H  03/1800Z 39.0N  50.0W   55 KT  65 MPH...POST-TROP/EXTRATROP
120H  04/1800Z 43.7N  47.6W   45 KT  50 MPH...POST-TROP/EXTRATROP

$$
Forecaster Papin